Immunohistochemical localization of interleukin-6 in human pancreatitis

Differential Roles of Interleukin-6 in Severe Acute Respiratory Syndrome-Coronavirus-2 Infection and Cardiometabolic Diseases

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection can lead to a cytokine storm, unleashed in part by pyroptosis of virus-infected macrophages and monocytes. Interleukin-6 (IL-6) has emerged as a key participant in this ominous complication of COVID-19. IL-6 antagonists have improved outcomes in patients with COVID-19 in some, but not all, studies. IL-6 signaling involves at least 3 distinct pathways, including classic-signaling, trans-signaling, and trans-presentation depending on the localization of IL-6 receptor and its binding partner glycoprotein gp130. IL-6 has become a therapeutic target in COVID-19, cardiovascular diseases, and other inflammatory conditions. However, the efficacy of inhibition of IL-6 signaling in metabolic diseases, such as obesity and diabetes, may depend in part on cell type-dependent actions of IL-6 in controlling lipid metabolism, glucose uptake, and insulin sensitivity owing to complexities that remain to be elucidated. The present review sought to summarize and discuss the current understanding of how and whether targeting IL-6 signaling ameliorates outcomes following SARS-CoV-2 infection and associated clinical complications, focusing predominantly on metabolic and cardiovascular diseases.

Interleukin 6 in diabetes, chronic kidney disease and cardiovascular disease: mechanisms and therapeutic perspectives

INTRODUCTION

Diabetes, chronic kidney disease (CKD) and cardiovascular disease (CVD) are cardiometabolic diseases that remain amongst the leading causes of morbidity and premature mortality. Here, we review the current understanding of how anti-inflammatory intervention via inhibition of the pro-inflammatory but pleiotropic cytokine interleukin (IL) 6 may benefit patients with these or related diseases or complications.

AREAS COVERED

Based on a PubMed literature search, this review integrates and contextualizes evidence regarding the clinical utility of anti-IL-6 intervention in the treatment of cardiometabolic diseases, as well as of the associated condition non-alcoholic hepatosteatosis.

EXPERT OPINION

Evidence implicates the pro-inflammatory effects of IL-6 in the pathophysiology of diabetes, CKD and CVD. Thus, targeting the IL-6 pathway holds a therapeutic potential in these cardiometabolic disorders. However, because IL-6 has multiple homeostatic roles, antagonizing this cytokine may be associated with side effects such as increased risk of infection as seen with other anti-inflammatory drugs. Additional studies are required to establish the benefit-risk profile of anti-IL-6 intervention in the cardiometabolic diseases, whilst also considering alternative interventions such as lifestyle changes. IL-6 is also elevated in NASH, but the clinical usefulness of targeting IL-6 in this hepatic disorder remains largely unexplored.

Association of Genetic Variants in IL6 Gene (rs1800795) with the Concentration of Inflammatory Markers (IL-6, hs-CRP) and Superoxide Dismutase in the Blood of Patients with Acute Pancreatitis—Preliminary Findings

In the course of acute pancreatitis, interleukin-6 plays an important role as a mediator in the inflammatory response. The course of inflammatory disease is associated with intensive oxidative stress, which may activate transcription factors leading to gene-expression changes. Isoenzymes of superoxide dismutase are involved in the defense against free radicals. This study aimed to evaluate changes in IL-6 concentration and the concentration/activity of superoxide dismutase isoenzymes (SOD1, SOD2, and SOD3) in the blood of patients with acute pancreatitis (AP) in terms of rs1800795 polymorphism in the IL6 gene. In the smoking AP patients group with the GC and GG genotypes, the plasma SOD1 concentration was significantly higher (p = 0.0146 and p = 0.0250, respectively) than in patients with CC genotype for SNP rs1800795 in the IL6 gene. An increase in SOD1 concentration in erythrocytes of AP patients with GC genotypes was also demonstrated compared to the individuals from the group with GG genotype (p = 0.0408). Furthermore, a positive correlation between IL-6 and SOD1 concentrations in the plasma of AP patients with GC genotype for SNP rs1800795 was shown. These results indicate that SOD1 may play a protective role against oxidative damage induced by inflammation in the group of AP patients with GC genotype.

Importance of Genetic Polymorphisms in MT1 and MT2 Genes in Metals Homeostasis and Their Relationship with the Risk of Acute Pancreatitis Occurrence in Smokers-Preliminary Findings

This study was aimed at evaluating the changes in metallothionein (MT) concentration in the blood of patients with acute pancreatitis (AP) and healthy subjects, taking into account the extracellular (plasma) and intracellular (erythrocyte lysate) compartments. The impact of single-nucleotide polymorphisms (SNPs) in the MT1A (rs11640851), MT1B (rs964372) and MT2A (rs10636) genes on MT concentration and their association with the concentration of metals (Cu, Zn, Cd) and ceruloplasmin as Cu-related proteins were analyzed. The concentration of a high-sensitivity C-reactive protein (hs-CRP) and IL-6 as markers of inflammation, and malonyldialdehyde (MDA), superoxide dismutase (SODs) activity and the value of total antioxidant capacity (TAC) as parameters describing the pro/antioxidative balance were also assessed. In the AP patient groups, an increased MT concentration in erythrocyte lysate compared to healthy subjects was shown, especially in individuals with the GG genotype for rs964372 in the MT1B gene. A Zn concentration was especially decreased in the blood of smoking AP patients with the AA genotype for SNP rs11640851 in the MT1A gene and the GC genotype for SNP rs10636 in MT2A, compared to non-smokers with AP, which was accompanied by an increase in the value of the Cu/Zn ratio. The exposure to tobacco smoke xenobiotics increased the risk of AP occurrence in subjects with the CC genotype for SNP rs11640851 in the MT1A gene by more than fourfold. The investigated polymorphisms, rs11640851 in the MT1A gene, rs964372 in the MT1B gene and rs10636 in the MT2A gene, seem to be an important factor in maintaining homeostasis in an organism under oxidative stress conditions.

IL-6 is present in beta and alpha cells in human pancreatic islets: Expression is reduced in subjects with type 1 diabetes

IL-6 is a pro-inflammatory cytokine upregulated in some autoimmune diseases. The role of IL-6 in the development of type 1 diabetes (T1D) is unclear. Clinical studies are investigating whether tocilizumab (anti-IL-6 receptor) can help preserve beta cell function in patients recently diagnosed with T1D. However, in some rodent models and isolated human islets, IL-6 has been found to have a protective role for beta cells by reducing oxidative stress. Hence, we systematically investigated local tissue expression of IL-6 in human pancreas from non-diabetic, auto-antibody positive donors and donors with T1D and T2D. IL-6 was constitutively expressed by beta and alpha cells regardless of the disease state. However, expression of IL-6 was highly reduced in insulin-deficient islets of donors with T1D, and the expression was then mostly restricted to alpha cells. Our findings suggest that the implication of IL-6 in T1D pathogenesis might be more complex than previously assumed.

Local and Systemic Expression of Immunomodulatory Factors in Chronic Pancreatitis

Inflammatory and fibrotic events that drive chronic pancreatitis (CP) are likely orchestrated via signaling of soluble cytokines and chemokines systemically and within the pancreas. However, a comprehensive summary of the expression of such factors during CP has not been reported to date. This information is important given continued interest in targeting cytokines that influence CP pathogenesis. Reported data on the expression change of soluble immunomodulatory factors in human CP patients were identified via a literature search using a single search term. Thirty-one articles meeting the prespecified inclusion criteria were identified to generate a compiled data summary. Compiled data demonstrated up-regulation of several factors in the blood or pancreas microenvironment of CP patients. Nine factors were elevated in both compartments, including fractalkine, IFN-γ, interleukin 1β, IL-6, IL-8, macrophage inhibitory cytokine 1, neutrophil gelatinase-associated lipocalin, transforming growth factor β, and tumor necrosis factor α. Most up-regulated factors could be classified into one of several functional groups, including inflammation, chemotaxis, angiogenesis, bone remodeling, extracellular matrix remodeling, and pain. After further validation, these factors may be used as biomarkers for disease diagnosis and identification of comorbidities, or as potential therapeutic targets.

Mathematical model of chronic pancreatitis

Chronic pancreatitis (CP) is a progressive inflammatory disease of the pancreas, leading to its fibrotic destruction. There are currently no drugs that can stop or slow the progression of the disease. The etiology of the disease is multifactorial, whereas recurrent attacks of acute pancreatitis are thought to precede the development of CP. A better understanding of the pathology of CP is needed to facilitate improved diagnosis and treatment strategies for this disease. The present paper develops a mathematical model of CP based on a dynamic network that includes macrophages, pancreatic stellate cells, and prominent cytokines that are present at high levels in the CP microenvironment. The model is represented by a system of partial differential equations. The model is used to explore in silico potential drugs that could slow the progression of the disease, for example infliximab (anti-TNF-[Formula: see text]) and tocilizumab or siltuximab (anti-IL-6/IL-6R).

Adipokines and cytokines in human pancreatic juice: unraveling the local pancreatic inflammatory milieu

BACKGROUND

Differential adipokine expression in obesity influences the inflammatory milieu, and may explain in part obesity's negative impact on pancreatic disease. Pancreatic juice analysis may provide a good means to evaluate the local pancreatic inflammatory milieu. The presence of adipokines in pancreatic juice is unknown.

AIMS

This proof-of-concept study was designed to determine the presence of adipokines and cytokines in human pancreatic juice.

METHODS

With institutional review board approval, pancreatic juice was obtained from ten patients with a broad range of diagnoses at the time of endoscopic retrograde cholangiopancreatography. Pancreatic juice was assayed using enzyme-linked immunosorbent assay (ELISA) for insulin, the proinflammatory adipokine leptin, the anti-inflammatory adipokine adiponectin, and the inflammatory mediators interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and monocyte chemoattractant protein-1 (MCP-1). Correlation between adipokine and inflammatory mediator expression was determined by linear regression analysis. Data are presented as mean +/- standard error of the mean (SEM); P < 0.05 was considered statistically significant.

RESULTS

Leptin (0.16 +/- 0.05 ng/ml) and adiponectin (0.63 +/- 0.02 microg/ml) were both present, as were the inflammatory mediators IL-6 (112.6 +/- 28.1 pg/ml), TNF-alpha (49.0 +/- 18.8 pg/ml), and MCP-1 (32.2 +/- 0.9 pg/ml). Paradoxically, the expression of the anti-inflammatory adipokine adiponectin correlated strongly with that of the proinflammatory cytokine IL-6 (R(2) = 0.98, P < 0.001).

CONCLUSIONS

This report is the first to describe adipokine expression in human pancreatic juice. Human pancreatic juice inflammatory mediators and adipokines may provide an important measurement of the local pancreatic inflammatory milieu.

Change of zinc, copper, and metallothionein concentrations and the copper-zinc superoxide dismutase activity in patients with pancreatitis

OBJECTIVES

The aims of the present studies were to measure the concentrations of zinc (Zn), copper (Cu), and metallothionein and the Cu/Zn superoxide dismutase activity as elements engaged in an essential manner in the prooxidative and antioxidative balance of organism and to demonstrate the degree to which metallothionein and Cu/Zn superoxide dismutase are involved in the inflammatory processes occurring in the pancreas.

METHODS

The concentration of metallothionein was measured by immunoenzymatic method. Serum Cu/Zn superoxide dismutase activity was determined using a commercial test. The measurements of Zn and Cu concentrations in serum were assessed with the use of flame atomic absorption spectrometry.

RESULTS

Lowered serum Zn concentration and higher Cu level were observed in the serum of patients with chronic exacerbated pancreatitis and chronic pancreatitis. The significant increase of metallothionein concentration and Cu/Zn superoxide dismutase activity was observed in the blood of patients with chronic exacerbated pancreatitis and chronic pancreatitis. In slices of the pancreas during pancreatitis, we observed in immunohistochemical reaction the variable involvement of Cu/Zn superoxide dismutase and metallothionein.

CONCLUSIONS

The results presented in these studies indicate an essential and variable involvement of antioxidants such Cu/Zn superoxide dismutase and metallothionein and disordered Cu and Zn homeostasis depending on the progression of inflammatory processes in patients with pancreatitis.